冻融作用下水泥改良土剪切强度试验研究  

Tests on shear strength of cement improved soil under freeze-thaw cycles

作　　者：赵安平[1,2] 汤爱平[1] 孙静[2] 于雪梅[2] 

机构地区：[1]哈尔滨工业大学土木工程学院,哈尔滨150090 [2]黑龙江大学建筑工程学院,哈尔滨150080

出　　处：《黑龙江大学工程学报》2015年第1期28-31,共4页Journal of Engineering of Heilongjiang University

基　　金：国家自然科学基金资助项目(51108163);黑龙江大学创新团队项目(Hdtd2010-13);黑龙江大学青年基金项目(QL201125)

摘　　要：季节性冻土区路基填料经历冻融作用,使道路出现翻浆冒泥、沉陷、强度弱化等问题,严重影响交通顺畅和行车安全。水泥改良土因可就地取材、性能良好、价格低廉,近年来被应用来改善冻害问题,而反复冻融作用对水泥土强度的损伤,是其在季冻区进一步推广应用的关键。以水泥改良粉质黏土为研究对象,通过冻融循环试验、强度试验,研究温度及冻融作用对其抗剪强度的影响,得到结论:1第1个冻融循环对改良土强度影响最大,表现在c值衰减快,且冻结温度越低,c值衰减越大;2随循环次数增加水泥土脆性特征明显,第7个循环后存在一个强度峰值,此后强度急剧降低,说明在第7次冻融时可能已经发生脆性破坏;3φ值随冻融次数增加呈小幅度的减小-增大-减小-增大的趋势,且温度越低,φ值减小幅度越小,增大的幅度越大。In seasonal frozen soil zones,roadbed fillings undergo freeze-thaw action,which will make road surface boiling,settling,weakening strength and so on,these impact traffic deeply,and have to be resolved.Recently,cement improved soil is used to figure out frost problems for it can be obtained locally,it has high property and lower price.But strength loss of cement soil during several freeze-thaw cycles affects its further apply in theset areas.In the research,cement improved silty clay is chosen as the object,freeze-thaw cycle tests and direct shear tests are acted to study how do freeze-thaw cycles influence shear strength of the soil.From lab data,some results are got：①the first cycle has most influence on shear strength,especially on cohesion c,c reduces quickly,and the lower temperature is helpful to reduce of c.②shear strength of the cement soil appears brittle with freeze-thaw cycles add,and there happens a peak value after seven cycle,then it reduce rapidly.Maybe,during the seventh cycle,a brittle destroy has been happened in soil body.③internal friction angle is reducing ＂ increasing＂reducing＂ increasing during cycles within a small range,andφlows less and rises more when temperature is lower.

关 键 词：水泥改良土 冻融循环 剪切强度 内聚力c 内摩擦角φ 

分 类 号：P642.116[天文地球—工程地质学]